Hydrocarbon oil conversion



Nov. 13, 1934. c HUFF 1,980,204

HYDROCARBON OIL CONVERSIO-N Filed March 50. 1931 FRACTIONATOR FURNACEFURNACE INVENTOR LYMAN C. HUFF ATTOR Y Patented Nov. 13, 1934 UNITEDSTATES PATENT OFFICE HYDROCARBON OIL CONVERSION Application March 30,1931, Serial No. 526,238

3 Claims.

This invention relates to'the treatment of hydrocarbon oils andparticularly refers to the conversion of relatively heavy oil or oils ofinferior quality into lower boiling products or, in general, intoproducts of a more .valuable nature.

The primary concepts of the present invention comprise separating therelatively light and 'the relatively heavy intermediate productsresulting from the conversion of hydrocarbon oil and subjecting each toindependently controlled conversion conditions in separate heatingelements, thence commingling the heated products and subjecting thecommingled materials to further conversion, thence separating the vaporsand the residual products of conversion, subject- "ing the vapors tofractionation in primary and secondary fractionating stages,subsequently condensing, cooling and collecting the desirable lightproducts of the operation.

As a feature of the invention a portion of the reflux condensate fromthe primary fractionating zone of the system alone or together with aportion of the raw oil charging stock may be cooled and returned to thereaction chamber for the purpose of cooling the products withdrawn fromthis zone to the subsequent vaporizing zone of the system. It is alsocontemplated returning the reflux condensate at any point before theintroduction of the products from the reaction zone to the vaporizingzone including points before and after the reduction in pressure.

' As another feature of the invention the raw oil charging stock may bepreheated by indirect contact with the vapors in the primaryfractionating zone and/or by indirect contact with the residual oilwithdrawn from the vaporizing zone and may thence be supplied all or inpart either to the primary or to the secondary heating eleinent or aportion or all of the raw oil may, if

desired, be fed directly into the primary fractionating zone to be fedtherefrom together with reflux condensate from this zone to the primaryheating element.

The attached diagrammatic drawing illustrates a specific embodiment ofone form of apparatus utilizing the principles of the present invention.The following description of the drawing embraces also a description ofthe process of the invention as it may be practiced in the apparatusillustrated. Raw oil charging stock may be supplied through line 1 andvalve 2 to pump 3 from which it may be fed through line 4 and valve 5into preheating coil 6, which may be located within fractionator '7 andwherein the oil may be preheated by indirect contact with the relativelyhot vapors in the fractionator. The preheated oil may thence passthrough line 8 and valve 9 into line 10 and thence through heatexchanger 11, where it may be further preheated by indirect contact withthe relatively hot residual oil from the system. The preheated oil maythence pass through line 12, line 13, valve 14 and line 15 into heatingelement 16 or from line 12 through line 17, valve 18 and line 19 intoheating element 20 or partially in both directions. If desired, a 05portion or all of the raw oil may by-pass preheating coil 6 and may passdirectly from line 4 to heat exchanger 11 through valve 21, in line 10.If desired, a portion or all of the raw oil, either in a relatively coldor in a preheated state,

may pass into direct contact with the vapors in -valve 27 into heatingelement 16.

Heatingelement 16 may be located within any suitable form of furnace 28and the oil supplied thereto may be heated to the desired conversion 5temperature under any desired pressure conditions and may pass throughline 29 and valve 30 into reaction chamber 31. Preferably heatingelement 16 and reaction chamber 31 are both maintained under asubstantial super-atmos- 9o pheric pressure and the pressure employed inchamber 31 may be substantially equalized with or lower than thatemployed in the heating element. Both liquid and vaporous products maybe withdrawn from chamber 31 through line 32 and valve 33 and may beintroduced into vaporizing chamber 34 which is preferably maintainedunder a substantially reduced pressure relative to that employed inchamber 31 and wherein vapors may separate from the residual products.

Residual oil may be withdrawn from chamber 34 through line35, valve 36,heat exchanger 11, 7 line 37 and valve 38 to further cooling'and storageor to any desired further treatment.

Vapors may be withdrawn from chamber'34 through line 39 and valve 41 tofractionator '1 wherein their relatively heavy insumciently convertedcomponents may be condensed to be returned to heating element 16, asalready described, for further conversion. Vapors from 110 fractionator7 may pass through line 42 and valve 43 to further fractionation infractionator 44. The relatively light desirable vapors may be withdrawnfrom fractionator 44 through line 45 and valve 46, may be subjected tocondensation and cooling in condenser 47, products from which may passthrough line 48 and valve'49 to be collected in receiver 50.Uncondensable gas may be released from receiver 50 through line 51 andvalve 52. Distillate may be withdrawn through line 53 and valve 54. Aportion of the distillate may, if desired, be withdrawn from receiver 50through line 55 and valve 56 to be recirculated by means of pump 57through line 58 and valve 59 to the upper portion of fractionator 44 toassist fractionation of the vapors in this zone.

The relatively heavy insufficiently converted components of the vaporssubjected to fractionation in fractionator 44 may be condensed in thiszone and may pass through line 60 and valve 61 to pump 62 from whichthey may be fed through line 63, valve 64 and line 19 to heating element20 for further conversion.

Heating element 20 may be located within any suitable form of furnace 65and the oil supplied to this zone may be heated, preferably to a moresevere conversion temperature than that employed in heating element 16,and the heated oil may pass through line 66 and valve 6'7 into line 29 pwhere it may commingle with the stream of heated oil discharged fromheating element 16, passing therewith into chamber 31. The pressureemployed in heating element 20 may be substan- 5 tially the same or maybe higher than that em- 3 ployed in chamber 31.

If desired, a portion of the relatively heavy reflux condensate orreflux condensate and raw oil, as the case may be, from fractionator 7may be 40 I diverted from line 15 and may pass through line or less. Thepreferred range of conversion conditions employed in the primary heatingelement are from 850 to 960 F. and from 100 to 350 pounds per squareinch or thereabouts; Substantially this same pressure range may beemployed in the reaction chamber although pressure in this zone may beof substantially the same or lower than that employed in the heatingelement. Conversion conditions employed in the secondary heating elementmay range preferably from 900 to 1200 F.. more or less, with pressuresranging from about 100 to approximately 350 pounds per square inch.Substantially reduced pressure relative to that employed in thereaction'chamber are preferably' maintained in the vaporizing,fractionating, condensing and collecting portions of the system. Therange of pressures in these zones is preferably of the order ofsubstantially atmospheric to approximately 100 pounds super-atmosphericpressure per square inch.

As a specific example of the operation of the straight-run gasoline.

with relatively heavy reflux condensate .from the primary fractionatorof the system. A temperature of about 900 F. and a pressure of about 300pounds per square inch are maintained in the primary heating element.This pressure is substantially equalized in the reaction chamber and isreduced in the subsequent vaporizing, fractionating, condensing andcollecting equipment to a substantially equalized pressure of about 40pounds per square inch. Relatively light reflux condensate from thesecondary fractionator of the system is subjected in the secondaryheating element to a temperature of approximately 940 F. under asuperatmospheric pressure of about 350 pounds per square inch, thepressure being reduced, of course, to about 300 pounds per square .inchprior to the introduction of these heated products into the reactionchamber. A suflicient quantity of the relatively heavy reflux condensatefrom fractionator 17 is recycled to the lower portion of the reactionchamber to insure a temperature of about 800 F. in the vaporizingchamber. This operation may yield approximately 62 percent of motor fuelhaving an anti-knock value approximately equivalent to a blend of 55percent benzol and 45 percent Pennsylvania In addition, about 30 percentof marketable fuel oil may be produced, the other products beinguncondensable gas and a relatively small percentage of coke orcarbonaceous material.

As an example of another type of operation, the charging stock is a 48A. P. I. gravity Pennsylvania distillate containing a substantialproportion of straight-run gasoline of poor antiknock value. Thismaterial is preheated and supplied, together with relatively lightreflux condensate from the secondary fractionator of the system, to thesecondary heating. element where it issubjected to a temperature ofapproximately 950' F. under a super-atmospheric pressure of about 350pounds per square inch.

Reflux condensate from the primaryfractionator' is subjected in theprimary heating element to a temperature of approximately 900 F. under asuper-atmospheric pressure of about 300 pounds per square inch. Apressure of about300 pounds per square inch is maintained in thereaction chamber and a reduced pressure of approximate- 'ly 50 poundsper square inch is maintained in the succeeding portions of the system.As in the preceding example a sufficient quantity of relatively heavyreflux condensate is returned to the lower portion of the reactionchamber to cool the products entering the vaporizing chamber to atemperature of approximately 800 F., this reduced temperature being due,however, in part to the pressure reduction between these two elements.This operation may yield approximately 87 percent of motor fuel havingananti-knock value approximately equivalent to a blend of 70 percentbenzol and 30 percent Pennsylvania straight-run gasoline. The only otherproducts are about 6 percent of residual oil and about 7 percent ofuncondensable gas, the coke production being negligible.

I claim as my invention:

1.,A hydrocarbon oil cracking process which comprises passing the oil ina restricted stream through a heating zone and heating the same processof the present invention at 31 A. P. I. gravity Pennsylvania toppedcrude is the raw oil charging stock which after preheating, in both ofthe means illustrated in the drawing, is supplied tothe primary heatingelement together therein to cracking temperature under pressure,discharging the heated oil into the upper portion of an enlargedreaction zone maintained under cracking conditions of temperature andpressure, removing the liquid and vaporous reaction products from thelower portion 01' the reaction zone and discharging the same into avaporizing zone maintained under lower. pressure than the reaction zone,separating the reaction products into vapors and residue in thevaporizing zone, subjecting the vapors to primary and secondarydephlegmation thereby forming primary reflux condensate and a; lightersecondary reflux condensate, commingling a sufiicient quantity of saidprimary reflux condensate with the reaction products being withdrawnfrom the lower portion of the reaction zone to effect substantialcooling of said products, continuously supplying another portion of saidprimary reflux condensate to the heating zone, passing said secondaryreflux condensate through a second heating zone and heating the sametherein to higher cracking temperature than the oil in thefirst-mentioned heating zone, discharging the thus heated refluxcondensate into the upper portion of the reaction zone, and finallycondensing the dephlegmated vapors.

2. A hydrocarbon oil cracking process which comprises passing the oil ina restricted stream through a heating zone and heating the same thereinto cracking temperature under pressure, discharging the heated oil intothe upper portion of an enlarged reaction zone maintained under crackingconditions of temperature and pressure, removing the liquid and vaporousreaction products from the lower portion oftheflreaction zone anddischarging the same into a vaporizing zonemaintained under lowerpressure than the reaction zone, separating the reaction products intovapors and residue in the vaporizing zone, subjecting the vapors toprimary and secondary dephlegmation thereby forming primary reflux vcondensate and a lighter secondary reflux condensate, commingling asufilcient quantity of said primary reflux condensate with the reactionproducts being withdrawn from the lower portion of the reaction zone toeffect substantial cooling of said products, said quantity ofthe-primary reflux condensate being forced under applied pressure intothe lower portion of the reaction zone in the direction of discharge ofthe reaction products therefrom, continuously supplying another portionof said primary reflux condensate to the heating zone, passing saidsecondary reflux condensate through a second heating zone and heatingthe same therein .to higher cracking) temperature than the oil in thefirst-mentioned heating zone, discharging the thus heated refluxcondensate into the upper portion of the reaction zone, and finallycondensing the dephlegmated vapors.

3. A hydrocarbon oil cracking process which comprises passing the oil ina restricted stream through a heating zone and heating the same thereinto cracking temperature under pressure, discharging the heated oil intothe upper portion of an enlarged reaction zone maintained under crackingconditions of temperature and pressure, removing the liquid and vaporousreaction products from the lower portion of the reaction zone anddischarging the same into a vaporizing zone maintained under lowerpressure than the reaction zone, separating the reaction products intovapors and residue in the vaporizing zone, dephlegmating the vapors indirect contact with charging oil for the process thereby forming amixture of charging oil and reflux condensate,

cooling a portion of said mixture and forcing the same under appliedpressure into the lower portion of the reaction zone in the direction ofdischarge of the reaction products therefrom, continuously supplyinganother portion of said mixture to the heating zone, furtherdephlegmating said vapors out of direct contact with charging oil toform a relatively light and clean secondary -reflux condensate, passingsaid secondary reflux condensate through a second heating zone andheating the same therein to higher cracking temperature than the oil inthe first-mentioned heating zone, discharging the thus heated refluxcondensate into the upper portion of the reaction zone, and finallycondensing the dephlegmated vapors. s

LYMAN C. HUFF.

